High efficiency transmitter

Abstract

The transmitter and method for transmitting a polarization-modulated signal include a driver for outputting a polarization-modulated signal based on a phase modulation signal and an amplitude modulation signal. A voltage regulator is connected to the driver, wherein the amplitude modulation signal controls the input of the voltage regulator, and wherein the amplitude modulation signal is further combined with the output of the voltage regulator to control the amplitude of the driver's output to compensate for bandwidth cutoff noise in the voltage regulator.

Description

Background Technology

[0001] This invention relates generally to transmitters, and more specifically to efficient transmitters that can be used in sensor arrays.

[0002] Low-power sensor arrays are increasingly being used in a variety of applications, including Internet of Things (IoT) devices, implantable devices, wearable devices, energy harvesting systems, seismic sensors, structural health monitoring systems, and multi-channel / multi-mode devices. While Cartesian transmitters have been used, these transmitters consume significant amounts of power. Summary of the Invention

[0003] A transmitter includes a driver for outputting a polarization-modulated signal based on a phase modulation signal and an amplitude modulation signal. A voltage regulator is connected to the driver, wherein the amplitude modulation signal controls the input of the voltage regulator, and wherein the amplitude modulation signal is further combined with the output of the voltage regulator to control the amplitude of the driver's output to compensate for bandwidth cutoff noise in the voltage regulator.

[0004] A phased array transmitter includes multiple radio front-ends, each transmitting a corresponding phase-shifted version of a polarization-modulated signal. Each radio front-end includes a driver and a voltage regulator. The driver outputs a polarization-modulated signal based on the phase-modulated signal and the amplitude-modulated signal. The voltage regulator is connected to the driver, wherein the amplitude-modulated signal controls the input of the voltage regulator, and wherein the amplitude-modulated signal is further combined with the output of the voltage regulator to control the amplitude of the driver's output to compensate for bandwidth cutoff noise in the voltage regulator. The phased antenna array transmits the phase-shifted polarization-modulated signal.

[0005] A method for transmitting a polarization-modulated signal includes applying a constant amplitude phase-modulated signal to a driver. An amplified control voltage is applied to the driver using a voltage regulator, wherein a first copy of the amplitude-modulated signal is applied to the input of the voltage regulator, and wherein a second copy of the amplitude-modulated signal is combined with the output of the voltage regulator to compensate for bandwidth cutoff noise in the voltage regulator. The polarization-modulated output of the driver is transmitted using an antenna.

[0006] These and other features and advantages will become apparent from the following detailed description of illustrative embodiments thereof, which will be read in conjunction with the accompanying drawings. Attached Figure Description

[0007] Preferred embodiments of the invention will now be described by way of example only and with reference to the following figures:

[0008] Figure 1 This is a comparison diagram of Cartesian modulation constellation diagrams and polarization modulation constellation diagrams suitable for modulating radio transmission according to embodiments of the present invention;

[0009] Figure 2 This is a block diagram of a transmitter using polarization modulation according to an embodiment of the present invention, wherein the amplitude portion is modulated onto the signal by controlling the output of an amplifier;

[0010] Figure 3 This is a circuit diagram of an amplitude control device according to an embodiment of the present invention, which uses a low-dropout voltage regulator output to control the amplitude of a driver based on an amplitude modulation signal.

[0011] Figure 4 This is a block diagram / flowchart of a method for transmitting a polarization-modulated signal, including the output of a control amplifier, according to an embodiment of the present invention.

[0012] Figure 5 This is a block diagram / flowchart of a method for generating angle signals and amplitude signals that can be used for polarization-modulated transmission according to an embodiment of the present invention;

[0013] Figure 6 This is a block diagram of a low-power sensor system according to an embodiment of the present invention, which generates polarization-modulated emission including amplitude modulation by controlling the output of an amplifier; and

[0014] Figure 7 This is a block diagram of a transmitter using polarization modulation and having multiple phase paths and multiple amplitude paths according to an embodiment of the present invention. Detailed Implementation

[0015] To improve transmitter efficiency, such as in low-power applications, polarimetric modulation can be used instead of Cartesian modulation. In such modulation schemes, the quadrature components of the transmitted signal can be used to represent "symbols" that encode a certain amount of information. Different types of modulation have different properties, such as different bandwidth requirements and different hardware.

[0016] The simplest such modulation scheme is on / off keying, where binary values ​​are encoded based on the amplitude of the transmitted signal. For example, a "high" amplitude can represent the first binary value, and a "low" amplitude can represent the second binary value. More complex modulation schemes include quadrature amplitude modulation (QAM), where two signals are transmitted simultaneously at a 90-degree angle to each other. These two signals can establish a two-dimensional space, where each point in the space can represent a different set of bits. By changing the amplitude levels of these two signals, many bits can be encoded using a single symbol.

[0017] Orthogonal amplitude modulation (OAM) is a form of Cartesian modulation where, in a two-dimensional symbol space, one signal represents the 'x' value and another signal represents the 'y' value, defining the position of the symbol along the corresponding x and y axes of the constellation. Each point in the two-dimensional symbol space represents a different symbol associated with a different corresponding bit sequence. Depending on the hardware and channel characteristics, different numbers of amplitude levels are possible, with more amplitude levels corresponding to constellations with higher density and more bits transmitted with each symbol.

[0018] While such Cartesian modulation schemes are common, they typically employ high-fidelity linear amplifiers. The amplitude of a Cartesian-modulated signal can change dramatically from one symbol to the next with abrupt shifts. To accurately represent these changes, a high-quality amplifier is required for transmission; otherwise, errors may be introduced. Linear amplifiers consume relatively large amounts of power, making them impractical for distributed and small transmitter designs.

[0019] In contrast, polarization modulation schemes use "radius" and "angle" values ​​to represent symbols in a two-dimensional symbol space. For example, the phase or frequency value of a signal can be encoded as an angle value, while the amplitude of the signal can be encoded as a radius value. The phase modulation input to the amplifier can then have a constant amplitude, so the amplifier does not need to accommodate large amplitude swings. Amplitude modulation of the polarization-modulated signal can then be performed by changing the amplifier's power output. The resulting output signal will vary in phase according to the phase of the input phase signal and will further vary in amplitude according to the control signal to the amplifier.

[0020] Now for reference Figure 1 The diagram illustrates a comparison between Cartesian symbol space 102 and polarized symbol space 106. Cartesian symbol space 102 comprises a set of Cartesian symbols 104, where the position of each symbol corresponds to a corresponding pair of values. These pairs of values ​​can be referred to as in-phase and orthogonal, and can correspond to values ​​on the x-axis and y-axis. Such values ​​can be emitted in orthogonal phase and combined within a single signal. Therefore, each of these paths can have a varying amplitude, and their combined signal will similarly vary in amplitude. When these signals are input to an amplifier, the amplitude of the combined signal can differ significantly from one symbol to the next. Amplifiers used for Cartesian modulated signals must precisely track the varying input power to prevent the introduction of distortion.

[0021] In the polarization symbol space 106, polarization symbols 108 correspond to corresponding value pairs, which may be referred to as angle and radius. Angle values ​​can be encoded as the phase or frequency of the signal, while radius values ​​can be encoded as the amplitude of the signal. A phase-modulated signal can be input with a constant amplitude 110, rather than changing the amplitude at the amplifier's input. The amplifier can then change its output to produce the final signal. Because the amplifier does not need to track changes in amplitude, a power-efficient nonlinear amplifier can be used.

[0022] Therefore, the amplitude can be changed by controlling the power of the amplifier (e.g., by controlling its supply voltage). Different mechanisms can be used to control this supply voltage, such as by using a voltage regulator.

[0023] A challenge in implementing low-power polarization modulation (e.g., using a low-dropout (LDO) regulator to control the supply voltage to the amplifier for amplitude modulation) is that the LDO circuit can have a bandwidth lower than the bandwidth to be used for transmission. When using an input signal with a bandwidth higher than that permitted by the LDO (e.g., a high-frequency range exceeding the bandwidth that the LDO can handle), the LDO can introduce distortion into the signal, for example, by cutting off a portion of the signal's spectrum.

[0024] To address this issue, the LDO's cutoff output is combined with a copy of the original input signal before the combined signal is used to control the amplitude output of the driver circuit. This copy helps recover the lost bandwidth while keeping distortion manageable.

[0025] Therefore, the Cartesian modulated signal can be expressed as:

[0026] Y C (t)=P I (t)cos(ω RF t)+P Q (t)sin(ω RF t)

[0027] Among them, P I (t) is the amplitude of the in-phase signal, P Q (t) is the amplitude of the orthogonal signal, ω RF Here, is the transmission frequency, and t is time. Simultaneously, the polarization-modulated signal can be expressed as:

[0028] Y P (t)=A(t)cos(ω RF t+θ(t))

[0029] Where A(t) is the amplitude modulation signal and θ(t) is the phase modulation signal. This can be defined... Know To convert Cartesian modulation into polarization modulation.

[0030] In Cartesian representation, orthogonal vectors can be used to represent modulated waveforms. Signals can be represented using in-phase (I) and quadrature (Q) terms, which can then be multiplied by the carrier frequency ω. RF The orthogonal phase. In polarization representation, the same signal can be represented by amplitude and phase, both of which vary with time. This represents the same information as Cartesian information, but can occupy a higher bandwidth. As the data rate increases, both amplitude and phase paths can occupy greater bandwidth.

[0031] Now for reference Figure 2 The image shows a transmitter 200 comprising a set of front-ends 210. Although multiple radio front-ends 210 are shown, for example for beamforming applications, it should be understood that this principle can also be applied to transmitters with only a single radio front-end 210. Each radio front-end 210 outputs a corresponding phase-shifted version of the transmitted signal to a corresponding antenna 206. These phase-shifted versions of the signal interfere with each other across multiple antennas, thereby creating spatial regions with relatively high and relatively low power, allowing the transmission to be focused onto a specific receiver.

[0032] The signal comprises a phase modulation section 202 and an amplitude modulation section 204. Although phase modulation is specifically envisioned, it should be understood that any suitable type of modulation, such as frequency modulation, can be used. These two parts of the signal may include different sets of information, such as different bit streams, both of which are included in a single transmission output.

[0033] Both signals are input to each radio front end 210. The phase modulation signal 202 can be generated using a phase-locked loop (PLL), which can be used to change the phase of the input signal relative to a reference signal. During operation, the PLL can further maintain synchronization between the phase modulation signal 202 and the amplitude modulation signal 204 if the two signals are to begin drifting away from each other.

[0034] Each radio front-end 210 has an amplitude path and a phase path, carrying its respective amplitude modulation signal 204 and phase modulation signal 202. On the phase path, the phase modulation signal 202 is shifted by a phase shifter 212 according to the beam steering direction. This phase-shifted phase modulation signal can be input to a driver 216 with a constant amplitude. The amplified power output of the driver 216 is controlled by an amplitude control circuit 214.

[0035] Amplitude control circuit 214 receives amplitude modulation signal 204 and uses it to control the power supplied to driver 216, thereby applying amplitude modulation to the phase-shifted phase-modulated signal. Since driver 216 only needs to process the phase of the input signal, it can be implemented using an inverter (e.g., a combination of a p-channel MOSFET and an n-channel MOSFET). Driver 216 can be implemented using switching amplifiers, where the supply voltage is modulated for higher efficiency while maintaining a wide bandwidth. For example, class AB, D, E, and F amplifiers can be used to implement driver 216. This transmitter architecture provides hundreds of times better power efficiency than systems using mixer-based transmitters.

[0036] Now for reference Figure 3 Additional details regarding the amplitude control circuit 214 are shown. An amplitude modulation signal 204 is provided as input. This input signal is used to trigger a replica circuit 304, which includes a copy of the driver 216 and feeds it into the LDO 302. The replica circuit 304 provides a scaled-down version of the primary driver 216, allowing accurate voltage tracking to be performed between the replica 304 and the driver 216. For example, if the primary driver 216 uses 1mA, the replica circuit 304 can be ten times smaller, drawing 100μA. This introduces low efficiency losses in the tracking implementation. Therefore, the replica circuit 304 can have the same basic structure as the driver 216, but with a design that appropriately scales down current consumption.

[0037] LDO 302 outputs a control signal to transistor 303, which provides the base output signal. The input amplitude modulation signal 204 further generates a bypass signal 306, which operates transistor 305 to combine with the base output signal. This provides a driver control output 308. The combined driver control output 308 is also fed back to LDO 302. By reintroducing the input signal 204 after LDO 302, out-of-band information lost due to the bandwidth constraints of LDO 302 is recovered. Furthermore, because the input and output of LDO 302 are affected by the same signal, the difference is canceled out, thus having no effect on the power supply rejection ratio of LDO 302.

[0038] Due to the periodicity of the waveform, any modulated signal in polarization form can provide an amplitude variation around the average value. For any waveform, an average value and a peak value can be defined. The ratio of the peak value to the average value is called the waveform's peak value and crest factor. The current mirror 309 provides a reference current, which is the average current I. AVG And the sum of the dynamic currents that vary around this average value. This can be further multiplied by the mirror ratio and provided to the reference voltage generator of the LDO 302. BBThe signal represents a dynamic current, and the corresponding switch provides an additional current proportional to the digital control word representing the amplitude modulation portion of the signal.

[0039] The LDO 302 can be designed to have a low quiescent current Io. Q and low bandwidth, low quiescent current I Q This indicates the current drawn when the LDO 302 is not activated. Furthermore, this architecture provides fast startup with a low time constant. Additionally, as data rates increase, larger bandwidth may be required for the amplitude and phase paths.

[0040] The voltage regulation loop of the LDO 302 can be designed to provide suppression of certain types of frequency-dependent noise from the unregulated voltage input. However, to provide this noise suppression, the LDO 302 can use a negative feedback loop that operates on a specific bandwidth. To avoid this bandwidth limitation, a digital code for amplitude modulation is provided to a current-guided element that provides a dynamic current proportional to the digital code and operates at high speed. The same current is provided to both the input and output of the LDO 302, one going to a copy circuit 304 and the other to a driver 216.

[0041] In some cases, a combination of coarse and fine step sizes can be used to perform amplitude modulation. For example, adjusting the coarse input controls which quadrant of the constellation the modulation symbol is in, while the fine input controls which point within that quadrant is used. Input 204 can therefore include multiple different input paths, such as a fine input path that controls a switch to add a current to input 204. A similar switch can be added to output 308, which can selectively redirect some amplitude of the output current to ground. In this way, fine amplitude changes can be provided on top of the coarse amplitude sent to amplitude control 214.

[0042] Now for reference Figure 7 Transmitter 700 is shown. The amplitude path can be segmented into multiple parallel paths, providing high efficiency and lower power consumption. Therefore, multiple amplitude control blocks 214 are shown, each capable of receiving an amplitude modulation section 204 independently. Each segment can operate on the quadrature phase of the phase path, and the signal can be reconstructed as the sum of multiple parallel paths. The quadrature phase from the phase-locked loop (PLL) 702 can also be used to create a constellation diagram for the specific modulation under consideration. The PLL 702 can use a frequency divider to provide the quadrature phase. Circuitry for providing a multiphase oscillator can also be used to provide the phase modulation waveform.

[0043] For example, phase modulation can be implemented using a PLL 702, wherein a phase shifter 706 provides corresponding phase shifts φ1, φ2, and φ3. nThese can be used to provide a specific phase shift to the phase-modulated signal generated in the PLL 702. These phase paths can also be configured in the corresponding amplitude control block 214. n A separate LDO is used to achieve higher efficiency and faster operation. Phase shifter 706 n It may include tunable passive components, delay components, or frequency dividers. Amplifier 216 n The output is combined at the signal adder 708 before passing to the matching network 710 and then to the antenna 206.

[0044] Now for reference Figure 4 The diagram illustrates a method for transmitting polarized modulated signals. Box 402 generates angle and amplitude signals. As will be described in more detail below, these signals encode positions in a two-dimensional symbol space corresponding to symbols, where each symbol represents a series of bits. As mentioned above, the angle signal can be encoded using any suitable form of keying, such as phase-shift keying or frequency-shift keying. Both signals are provided to each radio front end 210.

[0045] An angle signal (such as phase modulation signal 202) is applied to driver 216 of radio front end 210 in block 404. While it is specifically anticipated that the angle signal may have a constant amplitude, it should be understood that the angle signal may vary in amplitude within a predetermined range. Block 404 may include applying a phase shift to the angle signal before the angle signal is sent to driver 216.

[0046] In block 406, an amplitude signal is applied to amplitude control circuit 214. As described above, the amplitude signal can be applied to amplitude control circuit 214 at two points, including an injection point at the input of LDO 302 and an injection point combined with the output of LDO 302. Block 408 uses the output of amplitude control circuit 214 to control the power amplification of driver 216.

[0047] The output of driver 216 is a signal with polarization modulation. This signal is transmitted to antenna 206, for example, via a transmission line or matching network, and is transmitted at block 410. In the case of using an array of radio front-ends 210, each corresponding front-end 210 may execute blocks 404-410, where different phase shifts are applied to provide beam-directing effects.

[0048] Now for reference Figure 5This provides additional details regarding the generation of the angle and amplitude signals. Box 502 receives a bit stream containing the data to be transmitted and identifies bit sequences from that bit stream. The length of the bit sequence will depend on the type of polarization modulation scheme used. For example, in a modulation scheme with sixteen symbols, a four-bit sequence can be identified. Box 504 identifies the symbols corresponding to the identified bit sequences. This can be done using a lookup table, where each bit sequence is recorded with its corresponding symbol. Box 506 then determines the angle and radius values ​​corresponding to the symbols, for example, by looking up these values ​​in the lookup table. The angle and radius values ​​can also be calculated based on mathematical functions describing the modulation constellation.

[0049] Box 508 generates an angle signal based on an angle value. For example, the angle signal may include a phase shift or frequency shift, where the degree of offset from a certain base value corresponds to the angle value. Box 510 generates an amplitude signal based on an amplitude value. The amplitude signal may include a signal with a constant phase and frequency but varying according to its amplitude, where the degree of amplitude variation from a certain base value represents the amplitude value.

[0050] This invention can be a system, method, and / or computer program product with any possible level of technical detail integration. The computer program product may include a computer-readable storage medium (or media) having computer-readable program instructions thereon for causing a processor to execute aspects of the invention.

[0051] Computer-readable storage media can be tangible devices capable of retaining and storing instructions for use by an instruction execution device. Computer-readable storage media can be, for example, but not limited to, electronic storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disk read-only memory (CD-ROM), digital universal disk (DVD), memory sticks, floppy disks, mechanical encoding devices such as punch cards or protrusions in slots having instructions recorded thereon, and any suitable combination of the foregoing. As used herein, computer-readable storage media should not be construed as transient signals themselves, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through waveguides or other transmission media (e.g., light pulses passing through fiber optic cables), or electrical signals transmitted through wires.

[0052] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to a suitable computing / processing device via a network (e.g., the Internet, a local area network, a wide area network, and / or a wireless network), or to an external computer or external storage device. The network may include copper cables, optical fibers, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards them to a computer-readable storage medium within the suitable computing / processing device.

[0053] Computer-readable program instructions used to perform the operations of this invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, integrated circuit configuration data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​(such as Smalltalk, C++, etc.) and procedural programming languages ​​(such as the "C" programming language or similar programming languages). The computer-readable program instructions may be executed entirely on a user's computer, partially on a user's computer, as a standalone software package, partially on a user's computer and partially on a remote computer, or entirely on a remote computer or server. In the latter case, the remote computer may be connected to the user's computer via any type of network (including a local area network (LAN) or a wide area network (WAN)) or may be connected to an external computer (e.g., via the Internet using an Internet service provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGAs), or programmable logic arrays (PLAs) may execute computer-readable program instructions by utilizing state information from the computer-readable program instructions to personalize the electronic circuitry in order to perform aspects of this invention.

[0054] The present invention will now be described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It should be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer-readable program instructions.

[0055] These computer-readable program instructions may be provided to a processor of a computer or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create parts for implementing the functions / actions specified in one or more boxes of a flowchart and / or block diagram. These computer-readable program instructions may also be stored in a computer-readable storage medium that directs a computer, programmable data processing apparatus, and / or other device to operate in a particular manner, such that the computer-readable storage medium in which the instructions are stored comprises an article of manufacture containing instructions that implement aspects of the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0056] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer-implemented process, such that the instructions that execute on the computer, other programmable apparatus or other device perform the functions / actions specified in one or more boxes of a flowchart and / or block diagram.

[0057] As used herein, the terms "hardware processor subsystem" or "hardware processor" can refer to a processor, memory, software, or a combination thereof that cooperate to perform one or more specific tasks. In useful embodiments, a hardware processor subsystem may include one or more data processing elements (e.g., logic circuitry, processing circuitry, instruction execution devices, etc.). These one or more data processing elements may be included in a central processing unit, a graphics processing unit, and / or a separate processor- or computing element-based controller (e.g., logic gates, etc.). A hardware processor subsystem may include one or more on-board memories (e.g., cache, dedicated memory array, read-only memory, etc.). In some embodiments, a hardware processor subsystem may include one or more memories that may be on-board or off-board, or may be dedicated to use by the hardware processor subsystem (e.g., ROM, RAM, basic input / output system (BIOS), etc.).

[0058] In some embodiments, the hardware processor subsystem may include and execute one or more software elements. The one or more software elements may include an operating system and / or one or more applications and / or specific code for implementing a specified result.

[0059] In other embodiments, the hardware processor subsystem may include dedicated, specialized circuitry that performs one or more electronic processing functions to achieve a specified result. Such circuitry may include one or more application-specific integrated circuits (ASICs), FPGAs, and / or PLAs.

[0060] According to embodiments of the present invention, these and other variations of the hardware processor subsystem are also contemplated.

[0061] References to the invention in this specification as "one embodiment" or "embodiment" and other variations thereof mean that a particular feature, structure, characteristic, etc., described in connection with that embodiment is included in at least one embodiment of the invention. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing in various places throughout the specification, as well as any other variations, do not necessarily refer to the same embodiment.

[0062] It should be understood that, for example, in the cases of “A / B,” “A and / or B,” and “at least one of A and B,” the use of any of the following “ / ,” “and / or,” and “at least one of” is intended to include selecting only the first listed option (A), or only the second listed option (B), or selecting both options (A and B). As another example, in the cases of “A, B, and / or C” and “at least one of A, B, and C,” such wording is intended to cover only the selection of the first listed option (A), or only the selection of the second listed option (B), or only the selection of the third listed option (C), or only the first and second listed options (A and B), or only the first and third listed options (A and C), or only the second and third listed options (B and C), or all three options (A, B, and C). It will be apparent to those skilled in the art that this can be extended for many of the listed items.

[0063] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. Each block in a flowchart or block diagram may represent a module, segment, or portion of instructions, including one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the figures. For example, two blocks shown consecutively may actually be completed as a single step, executed simultaneously, substantially simultaneously, or with partial or complete temporal overlap, or the blocks may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented using a dedicated hardware-based system that performs the specified function or action or executes a combination of dedicated hardware and computer instructions.

[0064] Now for reference Figure 6An exemplary low-power sensor system 600 is illustrated. System 600 includes a hardware processor and memory 604. Sensor 606 may include one or more sensor components, each providing a measurement of one or more phenomena. As shown, sensor 606 may be on-board or may communicate with system 600 via any suitable communication interface and protocol.

[0065] Power supply 608 provides power to polarization modulation transmitter 610. Power supply 608 can be any suitable source, such as a battery, solar cell, vibration generator, piezoelectric generator, any suitable on-board or off-board generator, or external power supply. Specifically, power supply 608 is envisioned to have a relatively small size, enabling system 600 to be implemented in a cost-effective and space-efficient manner.

[0066] Transmitter 610 uses a power-efficient amplifier 216 to modulate the amplitude of the output signal, for example, by controlling the voltage supplied to amplifier 216. The phase of the output signal is controlled by adjusting the phase of the signal input to amplifier 216, which can be maintained at a constant amplitude. The modulated signal may include a measurement from sensor 606.

[0067] Transmitter 610 provides a modulated signal to antenna 612. Antenna 612 can use any suitable antenna configuration, such as a single antenna or a phased antenna array. In some cases, antenna 612 may include an antenna configuration for a single frequency band, in which case transmitter 610 may include a matching network 406 to make antenna 612 resonate at the transmission frequency.

[0068] In some cases, antenna 612 may include a phased array with multiple antenna elements. In such a case, each antenna element may transmit the same signal, but with different amounts of phase shift. The transmitted signals interfere constructively with each other in some places and destructively in others, providing a potentially very concentrated transmission pattern. Therefore, transmitter 610 may include phase shifters on each transmission path leading to the individual antenna elements of antenna 612, and the phase values ​​of these phase shifters may be adjusted according to a specific beam pattern.

[0069] Preferred embodiments of the high-efficiency transmitter have been described (these are intended to be illustrative and not restrictive), and it should be noted that modifications and variations can be made by those skilled in the art based on the foregoing teachings. Therefore, it should be understood that changes may be made to the specific embodiments disclosed within the scope of the invention as outlined in the appended claims. Various aspects of the invention, having the details and features required by patent law, have thus been described, and the claimed and desired protection by a patent certificate is set forth in the claims.

Claims

1. A transmitter, comprising: A driver used to output a polarization modulation signal based on a phase modulation signal and an amplitude modulation signal; A voltage regulator connected to the driver, wherein the voltage regulator is a low-dropout regulator; A replica circuit, having the same circuit structure as the driver but with lower current consumption, is fed into the voltage regulator and takes the amplitude modulation signal as its input. The amplitude modulation signal controls the input of the voltage regulator, and the amplitude modulation signal is further combined with the output of the voltage regulator to control the amplitude of the output of the driver. The output of the voltage regulator is combined with a copy of the amplitude modulation signal from the copy circuit before the combined signal is used to control the amplitude output of the driver to compensate for bandwidth cutoff noise in the voltage regulator.

2. The transmitter of claim 1, wherein, The bandwidth of the low-dropout regulator is lower than the bandwidth of the amplitude modulation signal.

3. The transmitter according to claim 1, wherein, It also includes a phase shifter that synchronizes the phase modulation signal and the amplitude modulation signal.

4. The transmitter according to claim 1, wherein, The phase-modulated signal has a constant amplitude.

5. The transmitter according to claim 1, wherein, The replica circuit is connected to the amplitude modulation signal and is parallel to the input of the voltage regulator.

6. The transmitter according to claim 1, wherein, The amplitude modulation signal includes a coarse amplitude adjustment part and a fine amplitude adjustment part.

7. The transmitter according to claim 1, comprising: Multiple radio front-ends, each transmitting a corresponding phase-shifted version of a polarized modulated signal; as well as A phased antenna array transmits a polarized modulated signal that has undergone phase shifting.

8. The transmitter according to claim 7, wherein, Each of the radio front-ends also includes a phase shifter that synchronizes the phase modulation signal and the amplitude modulation signal.

9. The transmitter according to claim 7, wherein, Each of the radio front-ends includes the copy circuit.

10. A phased array transmitter, comprising: Multiple radio front-ends, each transmitting a corresponding phase-shifted version of a polarization-modulated signal, each radio front-end comprising: The transmitter according to any one of claims 1-9; and A phased antenna array transmits a polarized modulated signal that has undergone phase shifting.

11. A method for transmitting a polarization-modulated signal, comprising: Apply a constant amplitude phase modulation signal to the driver; An amplified control voltage is applied to the driver using a voltage regulator, wherein an amplitude modulation signal is applied to the input of the voltage regulator, and wherein the amplitude modulation signal is combined with the output of the voltage regulator. The bandwidth cutoff noise in the voltage regulator is compensated by combining the output of the voltage regulator with a copy of the amplitude modulation signal from a replica circuit before the combined signal is used to control the amplitude output of the driver. The voltage regulator is a low-dropout regulator, and the replica circuit has the same circuit structure as the driver but with lower current consumption. The replica circuit is fed into the voltage regulator and takes the amplitude modulation signal as its input. The polarization modulation output of the driver is transmitted using an antenna.

12. The method according to claim 11, wherein, The bandwidth of the low-dropout regulator is lower than the bandwidth of the amplitude modulation signal.

13. The method according to claim 11, wherein, The amplitude modulation signal includes a coarse amplitude adjustment part and a fine amplitude adjustment part.

14. A computer program product comprising a computer program that, when executed by a processor, implements the method according to any one of claims 11 to 13.

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